Electrophysiological and Behavioral Effects of Combined Transcranial Direct Current Stimulation and Alcohol Approach Bias Retraining in Hazardous Drinkers.

BACKGROUND: Cognitive bias modification (CBM) can be used to retrain automatic approach tendencies for alcohol. We investigated whether changing cortical excitability with transcranial direct current stimulation (tDCS) could enhance CBM effects in hazardous drinkers. We also studied the underlying mechanisms by including behavioral (craving, implicit associations, approach tendencies) and electrophysiological (event-related potentials) measurements. METHODS: The analytical sample consisted of 78 hazardous drinkers (Alcohol Use Disorders Identification Test >8) randomly assigned to 4 conditions in a 2-by-2 factorial design (control/active CBM and sham/active tDCS). The intervention consisted of 3 sessions of CBM, specifically alcohol approach bias retraining, combined with 15 minutes 1 mA tDCS over the left dorsolateral prefrontal cortex. There was a pre- and postassessment before and after the intervention that included experimental tasks (Approach Avoidance Task, Implicit Association Task) and an electroencephalogram with an oddball and cue-reactivity task. RESULTS: tDCS decreased cue-induced craving (but not overall craving) on postassessment. CBM did not induce an avoidance bias during assessment. During the training, active and control-CBM only differed in bias score during the first session. We found no enhancement effects of tDCS on CBM. Electrophysiological data showed no clear effects of active tDCS or CBM on the P300. CONCLUSIONS: There were no electrophysiological or behavioral effects of repeated CBM and/or tDCS, except for an effect of tDCS on craving. Applied in these specific ways these techniques appear to have limited effects in a hazardous drinking population.

Prevalence of hazardous drinking among nursing students.

AIMS: To estimate the frequency of alcohol consumption among nursing students and describe their behaviour patterns in relation to excessive consumption. BACKGROUND: Most alcohol-related problems appear in individuals who indulge in hazardous consumption, with hazardous drinkers constituting a priority in the field of preventive activities. According to previous studies, there is a high proportion of hazardous drinkers among university students. DESIGN: Descriptive cross-sectional study. METHODS: Over the course of the 2012-2013 academic year, we assessed 1060 nursing degree students, ascertaining their socio-demographic characteristics, lifestyle and alcohol consumption by means of the Systematic Alcohol Consumption Interview (Interrogatorio Sistematizado de Consumos Alcohólicos/ISCA) and Alcohol Use Disorders Inventory Test (AUDIT). RESULTS: Hazardous alcohol consumption was observed in 43·4% of students. Moreover, 14·9% of men and 18·7% of women met criteria for hazardous drinkers, without any statistically significant difference between the sexes. The frequency of hazardous drinkers was significantly higher among participants aged under 21 years, those living outside the family nucleus and smokers. CONCLUSION: A considerable proportion of students show evidence of hazardous alcohol consumption and, while there are no sex-related differences, the proportion of hazardous drinkers tends to be higher among the youngest subjects, smokers and persons living outside the family nucleus. Alcohol-prevention activities should envisage greater protection of university settings, particularly where future health professionals are involved.

A Deep Learning Algorithm to Predict Hazardous Drinkers and the Severity of Alcohol-Related Problems Using K-NHANES.

Purpose: The number of patients with alcohol-related problems is steadily increasing. A large-scale survey of alcohol-related problems has been conducted. However, studies that predict hazardous drinkers and identify which factors contribute to the prediction are limited. Thus, the purpose of this study was to predict hazardous drinkers and the severity of alcohol-related problems of patients using a deep learning algorithm based on a large-scale survey data. Materials and Methods: Datasets of National Health and Nutrition Examination Survey of South Korea (K-NHANES), a nationally representative survey for the entire South Korean population, were used to train deep learning and conventional machine learning algorithms. Datasets from 69,187 and 45,672 participants were used to predict hazardous drinkers and the severity of alcohol-related problems, respectively. Based on the degree of contribution of each variable to deep learning, it was possible to determine which variable contributed significantly to the prediction of hazardous drinkers. Results: Deep learning showed the higher performance than conventional machine learning algorithms. It predicted hazardous drinkers with an AUC (Area under the receiver operating characteristic curve) of 0.870 (Logistic regression: 0.858, Linear SVM: 0.849, Random forest classifier: 0.810, K-nearest neighbors: 0.740). Among 325 variables for predicting hazardous drinkers, energy intake was a factor showing the greatest contribution to the prediction, followed by carbohydrate intake. Participants were classified into Zone I, Zone II, Zone III, and Zone IV based on the degree of alcohol-related problems, showing AUCs of 0.881, 0.774, 0.853, and 0.879, respectively. Conclusion: Hazardous drinking groups could be effectively predicted and individuals could be classified according to the degree of alcohol-related problems using a deep learning algorithm. This algorithm could be used to screen people who need treatment for alcohol-related problems among the general population or hospital visitors.

Are hazardous drinkers more impulsive than light drinkers? A comprehensive assessment in young adults.

Those with alcohol dependence are characteristically impulsive. It is unclear whether the same is true of hazardous drinkers (i.e., women routinely drinking more than 14 units in a typical week but fewer than 35, and men drinking more than 14 units but fewer than 50). Yet, it is important to understand the mechanisms involved in such drinking, since it places the drinker at risk for future harm. The present study thus comprehensively assessed whether impulsivity was elevated in hazardous drinkers, compared to lighter drinkers. An opportunity sample of 57 light and 49 hazardous drinkers was assessed on the following impulsivity subdomains (via the measures in parentheses): (i) trait impulsivity (the Barratt Impulsiveness Scale, Version 11); (ii) temporal impulsivity (the Monetary Choice Questionnaire); (iii) stopping impulsivity (the Stop-Signal Task); (iv) waiting impulsivity (the Continuous Performance Task or CPT); (v) reward-sensitivity (the Behavioural Activation Scales); and (vi) risk-taking (the Balloon Analogue Risk Task). Alcohol- and other drug-dependent individuals were excluded from the study, while socio-demographics (age, gender, and socio-economic status), mood, binge drinking, and nicotine intake were all controlled for. The groups were compared via a series of Bonferroni-corrected, independent-measures t tests. The results revealed that hazardous drinkers were more impulsive than light drinkers on the CPT; there were no other statistically significant group differences. Consistent with the above, a logistic regression, with drinking group as the dependent variable and the impulsivity indices as independent variables, revealed that only CPT performance was a significant predictor of drinking status. Other than gender, none of the control variables significantly correlated with CPT performance. A sequential linear regression revealed that drinking status continued to predict CPT performance, after first accounting for gender. Thus, from a battery of impulsivity measures, only waiting impulsivity (i.e., CPT score) was elevated in hazardous drinkers, relative to lighter drinkers. Waiting impulsivity may thus be important in the maintenance of hazardous drinking.

Sex differences in the relationship between heavy alcohol use, inhibition and performance monitoring: Disconnect between behavioural and brain functional measures.

Previous research has reported mixed evidence of sex differences in the relationship between heavy alcohol use and deficits in behavioural control. Here, we examine sex differences in behavioural and event-related potential (ERP) markers of deficient inhibition. Participants were 71 young adults aged 18-21, who either drank heavily regularly (i.e., four standard drinks on one occasion, at least once a month, n=33, 20 male) or drank heavily less often than this (including never, n=38, 21 male). They completed a stop-signal task while ERPs were recorded. Increases in stop-signal reaction time, the time required to stop a response, were related to heavy drinking only in female participants. P3 amplitude, ERN amplitude and ERN latency did not display a significant interaction between group and sex. Heavy drinkers, regardless of sex, displayed a marginally larger successful>failed effect for P3 amplitude, and a marginally smaller error-related negativity. An apparent disconnect exists in behavioural and psychophysiological measures of sex differences in the relationship between heavy alcohol consumption and inhibitory processing; male heavy drinkers display only psychophysiological but not behavioural deficits, while female heavy drinkers display both. Future research may determine whether sex differences are apparent for other substances besides alcohol.

The manipulation of alcohol-related interpretation biases by means of Cognitive Bias Modification--Interpretation (CBM-I).

BACKGROUND AND OBJECTIVES: There is a large body of evidence demonstrating that alcohol abuse and misuse is characterized by alcohol-related interpretation biases (IBs). The present study tested whether alcohol-related IBs can be trained, and whether this has an effect on alcohol-related associations and drinking behavior. A newly developed alcohol Cognitive Bias Modification - Interpretation (CBM-I) training was employed. The potential moderating effect of executive control on CBM-I training effects was tested. METHOD: Participants were hazardously male drinking students. A classical Stroop was used to assess levels of executive control. Half of the sample was trained to interpret ambiguous alcohol-related scenarios in an alcohol-related manner (alcohol training group), whereas the other half was trained to interpret ambiguous alcohol-related scenarios in a neutral manner (neutral training group). A Single Target Implicit Association Test (STIAT) was used to test whether the training would generalize to implicit alcohol-related associations (target words: alcohol, attributes: positive vs. neutral). To test the training's effect on drinking behavior, a bogus taste test and a one week follow-up measure assessing participant's real life drinking behavior were used. RESULTS: The CBM-I training was partly successful: When presented with novel ambiguous alcohol-related scenarios, participants of the alcohol training group interpreted these scenarios as more alcohol-related after the training. However, there was no reduction in alcohol-related IBs in the neutral training group. Results of the STIAT demonstrated that both training groups showed stronger positive than neutral alcohol-related associations. However, there were no between-group differences in alcohol-related associations. Moreover, the CBM-I training's effect was not moderated by levels of executive control. Finally, no group differences were found on levels of alcohol consumption (bogus taste test and at one week follow-up). LIMITATIONS: The neutral training might have been operationalized sub-optimally. A multi-session training might have resulted in stronger effects. CONCLUSIONS: These findings are the first to show that alcohol-related IBs can be trained. However, the training effect only partly generalized so more research is needed to advance our understanding of alcohol CBM-I effects.

Approach-avoidance pattern of visual attention in hazardous drinkers with ambivalence.

Ambivalence toward alcohol often develops when hazardous drinkers try to quit or to control their drinking. The purpose of this study was to investigate the differences between hazardous drinkers with and without ambivalence toward alcohol in terms of their visual attention to alcohol-related pictures over time using an eye-tracker. The study included 20 hazardous drinkers with ambivalence and 21 hazardous drinkers without ambivalence. The eye movements of the participants were monitored while the participants conducted a free-viewing task in which 20 pairs of alcohol-related pictures and matched control pictures were presented. The results showed that the hazardous drinkers with ambivalence were more attentive to the alcohol-related pictures at first and were more attentive to the control pictures toward the end of the task. On the other hand, the hazardous drinkers without ambivalence were more attentive to the alcohol-related pictures from beginning to end. The findings of this study indicated that ambivalence toward alcohol resulted in the inclination to approach and then avoid alcohol in a consecutive sequence. The present results could be helpful in distinguishing hazardous drinkers who may have ambivalence toward alcohol and identifying the pattern of ambivalence more concretely. Additionally, further studies need to consider the time that is important to measure ambivalence toward alcohol.

Evidence of deficits in behavioural inhibition and performance monitoring in young female heavy drinkers.

BACKGROUND: New models of the development and maintenance of substance abuse give increasing importance to the role of deficits in inhibitory function. Much of the evidence to support this claim comes from male participants, despite some researchers showing greater disinhibition in females. Clearly, more research on female heavy drinkers is warranted. In this study, we examine behavioural and psychophysiological measures of inhibitory function in female young adults who do and do not regularly drink heavily. METHODS: Participants were thirty female young adults (aged 18-21) who drink heavily (four or more standard drinks per occasion) at least once a month (n=13) or who drink heavily less often than this (n=17); none regularly used any other drugs, including tobacco. They underwent interviews assessing prior use of alcohol, before completing a stop-signal task while brain electrical activity was recorded. RESULTS: Regular heavy drinkers displayed a longer stop-signal reaction time (the time required to stop an inappropriate response), and a larger P3 increase for successful compared to failed inhibition trials. Heavy drinkers also displayed a smaller error-related negativity (ERN) amplitude, indexing a deficit in performance monitoring. CONCLUSION: These results indicate that large deficits in inhibitory processing and performance monitoring occur in young female heavy drinkers, and that heavy drinkers may have to work harder in order to successfully inhibit a response. Future research may determine whether these deficits pre-date or are caused by alcohol abuse.